1) Technical Field
The subject invention relates to a gripping tool disposed on a robot manipulator for gripping and moving various objects between desired locations.
2) Description of the Prior Art
Robot manipulators are frequently used in modern manufacturing plants and distribution centers for accomplishing such tasks as material handling, machine loading and unloading, parts transfer, manufacturing assembly, waterjet cutting, die casting, dispensing, welding, painting, and material removal. These robots usually have a rotatable base with a manipulating arm. The arm includes a shoulder section, elbow section and a wrist section. A tool is typically mounted to the wrist section for performing a desired operation. The tool may be any type of suitable device such as needed to perform the operation. Gripping tools are commonly used for clasping, lifting, holding, placing and transporting objects from one point to another.
A common type of gripping tool typically has a lift arm which projects outwardly to support and lift the object. Clamps are often provided to sandwich the object between the clamp and the lift arm to hold the object to the gripper. One such example of a gripping tool is disclosed in U.S. Pat. No. 4,696,501 to Webb. A deficiency encountered with the prior art grippers relates to releasing the object from the gripper tool. To release the object, the clamp lifts upwardly and then the gripping tool must be angled downwardly to have the object fall or slide off of the lift arms. The object falls off solely due to the force of gravity. This creates an unstable environment wherein the object may be positioned incorrectly or damaged. In addition, there may be instances where the robot has limited space and cannot manipulate the gripper tool effectively to unload the object. Finally, the programming of the robot is more complex and requires additional set up time to add the additional movements of the gripper tool. Hence, it is desirable to have a pusher type device on a robot gripper tool for pushing the object off of the lift arm and onto a desired location.
As disclosed in U.S. Pat. No. 4,395,190 to Barchard, the prior art has contemplated the use of a pusher device on a fork lift truck for pushing an object off of a pair of lift arms. This assembly, however, does not have a clamp device for holding the object in place during transport. In addition, the pusher and lift arms are not manipulatable and could not be used on a robot gripping tool.